摘要
用氧电极法测定了两个品种小麦线粒体有关呼吸功能的3项指标,研究其冻害问题。结果表明,-15℃低温促进了线粒体呼吸状态4耗氧量的增大,对呼吸控制率(呼吸状态3与呼吸状态4的比值)和磷氧比却有降低作用,NaCl更加剧了零下低温(-15℃)对线粒体的伤害。零上低温(2℃)锻炼有削弱或减缓线粒体冻害的作用。小麦品种之间对-15℃低温或NaCl的反应有差异。说明线粒体膜是冻害的位点之一,膜结构和功能是一致的,线粒体能量代谢失调可能是冻害的部分原因。
In order to understand the mechanism of freezing resistance in plants,the changes of O_2 consumption, respiratory control ratio and P: O ratio inisolated wheat mitochondria from etiolated wheat seedlings (Triticnmaestivnm L. cv Dongfanghong No. 3, freezing-rrsistant, and Fengqiang No. 3,freezing-sensitive) after treated with-15℃ low temperature were studiedwith oxygen electrode. The iesults are as follows: The O_2 consumption rate of respiratory state 4 in wheat mitochondriawas stimulated respiratory control ratio and P: O ratio were decreased by-15℃.low temperature treatment. The injury of the low temperature on thewheat mitochondria was even more significant by NaCl Cold hardeningunder 2℃ temperature had an effect of retard on the freezing injury of wheatmitochondria. The increaceds of O_2 consumption rate, the ratio of respir-atory control and P: O in mitochondria of resistant wheat cultivar Dong-fanghong No. 3 were lower or higher than those of sensitive wheat cultivarFengqiang: No.3,respectively. It illustrates that the wheat mitochondriamembrane is site of freezing injury, and unity between structure and functionfor biomembrane. The difference of reaction at -15℃ low temperature or in NaCl andthe correlation between structure and function of mitochondria and freezingresistance in plant were discussed.
关键词
小麦
线粒体
呼吸功能
低温
Wheat mitochondria
Respiratory function
Freezing resistance
